In my old theater classes, we were taught that Oklahoma! (1943) was the first Broadway musical where the songs advanced the plot. Called the first “integrated musical,” it has grabbed its rightful spot as the first of the “modern” stage musicals while overshadowing its powerful predecessor.

It was actually Showboat (1927) that was the revolutionary musical, albeit a bit creaky when compared to Oklahoma! Yes, it was more a dramatic musical epic than any kind of “musical comedy,” and its themes of racism, miscegenation, abandonment, despair and alcoholism certainly set it apart—and still does—from other musical stories. But its songs and how they were used were light years ahead of those in vaudeville and other musical revues of the time. “Make Believe,” “Ol’ Man River,” “Can’t Help Lovin’ Dat Man”—these are all classics that carry the story forward as no other show songs had done.

The challenge with people recognizing Showboat for its place in history is that it was a standalone for too long. No one took the ball and ran with it. Rodgers and Hammerstein (the latter being the lyricist of Showboat) reinvented and reinvigorated the integrated musical with Oklahoma! and then others paid attention and copied. Showboat was the first integrated stage musical, but Oklahoma! began the trend.

But the film person in me isn’t content to let the matter lie there. Four years before Oklahoma! there was a little musical that was completely integrated. It just happened to be a film musical featuring a girl from Kansas, a little dog, a scarecrow, a tin man and a timid lion. “Somewhere Over the Rainbow;” “We’re Off to See the Wizard,” “Ding-Dong!, the Witch is Dead,” “If I Only Had a Brain”—these move the story along as well as those in Oklahoma!’s score. It’s just that The Wizard of Oz (1939) was a film.

Perhaps a little more looking over the fence to related art forms would help to clarify and bolster the history of all the arts.